JPH0455323A - Blue-green pigment of fine-grained multiple oxide and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a fine particle composite oxide blue-green pigment and a method for producing the same, which is transparent and has a specific surface area of 50 r
An object of the present invention is to provide a green-tinted fine particulate composite oxide blue-green pigment with good dispersibility of /g or more.

(Prior Art) Complex oxide blue-green pigments are widely known as inorganic pigments with excellent heat resistance, and are widely used, for example, as colorants for paints, synthetic resins, and ceramics.

The above-mentioned blue-green pigment is a spinel type compound consisting of oxides of aluminum, cobalt and chromium, and is produced mainly by a dry method by mixing, firing and pulverizing oxides of aluminum, cobalt and chromium and a carbonaceous compound.

However, the above-mentioned dry method has the drawback that it requires a large amount of energy for pulverization, and the current situation is that fine particles cannot be obtained because the sintered body is pulverized. Furthermore, blue-green pigments have not been industrially produced by the wet method until now.

(Problem to be solved by the invention) The dry method mixes aluminum, cobalt, chromium oxides, etc.
This method involves firing at high temperature in the presence of flux, and then pulverizing the sintered particles using a powerful crusher to form pigments.However, unless the constituent oxides are fine particles, the fired product will not be transparent. It is difficult to form fine particles, and even if such fine particles exist, they are sintered during firing and require a large amount of energy for pulverization.

On the other hand, in the case of the wet method, fine-grained blue-green pigments are obtained by co-precipitating a mixed metal salt solution containing dissolved salts of aluminum, cobalt, and chromium using an alkali such as caustic soda as a precipitant and firing. However, the market demand was for a greener color as an intermediate color between blue and green. -The higher the proportion of chromium in a ship, the greener it tends to be; however, as the proportion of chromium increases (
It is difficult to obtain a transparent blue-green pigment with a greenish tint because it has a dull green tint and the particles become large and lose transparency.

(Means for Solving the Problems) As a result of intensive research in order to meet the demands of the above-mentioned prior art, the present invention has been developed by adding titanium to the three constituent elements of aluminum, cobalt and chromium in a wet precipitation method to form four components. It has been discovered that the desired properties can be satisfied by producing a complex oxide pigment.

That is, the present invention is made of oxides of aluminum, cobalt, chromium, and titanium, and has a BET specific surface area of 50 nf/
A fine particle composite oxide blue-green pigment characterized by a particle size of more than This is a method for producing a fine particle composite oxide blue-green pigment, which comprises coprecipitating and aging each salt, followed by filtration, washing with water, drying and firing.

(Function) A titanium compound is further added to the mixed solution of aluminum salt, cobalt salt, and chromium salt to form a mixed solution of four components, and this is co-precipitated using a precipitating agent such as an aqueous alkaline solution, resulting in good transparency. However, it also has a green taste,
A greenish fine-particle composite oxide blue-green pigment that develops color sufficiently even when fired at a relatively low temperature can be obtained.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The salts of each constituent element other than titanium used in the present invention include sulfates, nitrates, carbonates, chlorides, acetates, etc., all of which are conventionally used in producing complex oxide blue-green pigments. I can do it. In the case of titanium, reagents or industrial raw materials such as titanium tetrachloride and titanyl sulfate can be used.

In the above, the composition ratio of each component is the metal molar ratio: aluminum: cobalt: chrome cotitanium = 1: l: 2:0
．． 4 is the most preferred; at this ratio, a greenish, transparent blue-green color is produced.

Further, according to the results of research conducted by the present inventors, the molar ratio of the above-mentioned constituent components aluminum (Al), cobalt (Co), chromium (Cr), and titanium (Ti) is 0.5 aluminum to 1 cobalt. ~2.0, chromium 0.1-3
It was also found that changes in composition within the range of 0.1 to 0.6 titanium did not significantly affect transparency.

Also, as the proportion of aluminum increases, the blueness increases,
Conversely, as the proportion of chromium increases, the color becomes greener, but if there is too much chromium, the color tends to become dull. The appropriate molar ratio is 0.4 titanium to cobalt 1,
If the amount is more than that, transparency tends to be lost, and if it is less than that, the color does not develop a good greenish tinge, which is inappropriate.

The metal salts of the constituent elements as described above are dissolved in water to form a mixed salt aqueous solution. The concentration at this time is suitably about 5 to 50% by weight as a whole based on the above molar ratio. This mixed solution is simultaneously dropped into a precipitation medium prepared in advance using an alkaline aqueous solution such as caustic soda as a precipitant.

The reaction concentration at this time does not have a particularly bad effect on transparency, but considering workability, etc., the reaction concentration ranges from 0.05 mol/β to 0.05 mol/β.
A value of 5 mol/β is appropriate, and the lower the concentration, the better the transparency tends to be. Further, as long as the synthesis temperature is in the usual range, that is, in the range of 0°C to 100°C, the effect can be sufficiently exhibited as before. In addition, the pH at the time of synthesis
If it is in the range of 7 to 10, transparency will not be significantly impaired. However, as the pH shifts to the alkaline side, the transparency tends to increase slightly, while as the pH shifts to the acidic side, it becomes whitish and the transparency tends to decrease.

After forming a precipitate while stirring for 30 minutes to 1 hour in this manner, the mixture is aged for about 1 hour to complete the precipitation reaction.

Next, by filtering the precipitated coprecipitate, the water content will be about 40% to 80%, so it will be heated to 100℃ to 120℃.
Dry at a temperature of about
Bake at a temperature of ~1000°C for 30 minutes to 1 hour to develop color. As a result, the greenish fine particle composite oxide blue-green pigment of the present invention can be obtained.

The fine particle composite oxide blue-green pigment of the present invention obtained in this way has a clearer and deeper color tone than that obtained by the conventional dry method, is easier to crush, and is made of four components by adding titanium. By making it into a pigment system, it is possible to create an excellent pigment with a greener color and transparency.

(Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. It should be noted that unless otherwise specified, the terms in the text or % are based on weight.

Example 1 Aluminum nitrate nonahydrate 37.51 parts, cobalt nitrate 6
29.10 parts of aqueous salt, 80.03 parts of chromium nitrate nonahydrate, and 11.7 parts of titanium tetrachloride aqueous solution containing 2916.3% by weight of titanium nitrate.
Measure out 6 parts and add it to water to dissolve completely and make about 5 parts.
00 copies. Next, 51.0 parts of caustic soda as a precipitant was weighed out and water was added to make a total of about 500 parts.

200 parts of water, which is a precipitation medium prepared in advance, is heated to about 30°C using a gas burner or electric heater, and mixed salt aqueous solution and caustic soda aqueous solution are simultaneously added dropwise thereto for about 30 minutes to 1 hour. to complete the precipitation reaction. At this time, care is taken to keep the pH at 9, and once the dropwise addition is complete, the pH is raised to about 10 to ensure complete precipitation, and the solution is aged for about 1 hour while maintaining the temperature at 30°C.

Next, when the ripening is completed, it is taken out and thoroughly washed with water by decantation to remove residual salt and filtered. It is then dried at a temperature of 100°C to 120°C for 12 hours or more. This dried product is fired at 800° C. for 1 hour in an oxidizing atmosphere.

The pigment thus obtained had fine particles, a BET specific surface area of 86 rrr/g, and a deep green color with transparency.

The fired product is then dispersed in melamine alkyd resin (PHR40) using a paint shaker.

The color was then applied to black art paper using a 6 mil applicator and the color tone was observed.

Example 2 Chiku 2033. % titanyl sulfate dihydrate by weight 9.48
1 part to 200 parts of water prepared in advance and stir to completely dissolve. Next, as in Example 1, measure out aluminum nitrate hexahydrate, cobalt nitrate hexahydrate, and chromium nitrate hexahydrate,
In addition to this, water is added so that the total amount is 500 parts to completely dissolve and prepare a mixed salt aqueous solution.

The pigment obtained in the same manner as in Example 1 had fine particles, a large specific surface area, a green tint, and was transparent.

Comparative Example 1 101.96 parts of aluminum oxide, 74 parts of cobalt oxide.
93 parts, chromium oxide 303.98 parts, titanium oxide 31.
Measure and mix 96 parts. This is fired at 800°C. Next, this fired product was crushed to obtain a sample.

As described above, the pigment obtained by the dry method did not have sufficient color development compared to the pigment obtained in Example 1, and had a whitish appearance as a whole and lacked transparency.

The above results are summarized in Table 1.

* Hue/transparency: Melamine alkyd resin HR40 (Effects) As described above, according to the present invention, a fine particle composite oxide blue-green pigment with sufficient color development, deep green tinge, and excellent transparency can be obtained. Similar to conventional pigments, the pigment is used as a coloring agent for general paints, synthetic resins, and ceramics, and its properties are used to create transparent paints, transparent thin films, printing inks, etc. It is expected to be applied to cosmetics, phosphors, abrasives, etc.

Patent applicant: Dainichiseika Industrial Co., Ltd. 1 other person Ra,・Shinding 1 other person

Claims (7)

[Claims] (1) A fine particle composite oxide blue-green pigment comprising oxides of aluminum, cobalt, chromium, and titanium, and having a BET specific surface area of 50 m^2/g or more. (2) The molar ratio of the constituent components aluminum (Al), cobalt (Co), chromium (Cr), and titanium (Ti) is 0.5 to 2.0 aluminum and 0.1 to 3 chromium to 1 cobalt. and titanium in a range of 0.1 to 0.6, the fine particle composite oxide blue-green pigment according to claim 1. (3) Dissolve the four components of aluminum salt, cobalt salt, chromium salt, and titanium compound in water to make a mixed salt solution, coprecipitate each salt using an aqueous alkali solution as a precipitant and age, then filter, wash, and dry. A method for producing a fine particulate composite oxide blue-green pigment, comprising: (4) The method for producing a particulate composite oxide blue-green pigment according to claim 3, wherein coprecipitation is carried out by simultaneously adding a mixed salt solution and an alkaline solution to a coprecipitation medium. (5) The method for producing a particulate composite oxide blue-green pigment according to claim 3, wherein the firing temperature is 600°C or higher. (6) Claim 3, wherein the pH during coprecipitation is within the range of 7 to 10.
A method for producing a fine particle composite oxide blue-green pigment as described in . (7) The molar ratio of the constituent components aluminum (Al), cobalt (Co), chromium (Cr) and titanium (Ti) to 1 cobalt: 0.5 to 2.0 aluminum and 0.1 to 3 chromium. and titanium in a range of 0.1 to 0.6, the method for producing a fine particle composite oxide blue-green pigment according to claim 3.